1. Field of the Invention
The present invention relates to a method for forming a cured-resin layer having an antistatic surface. More specifically, the present invention relates to a method for forming an ultraviolet-cured resin layer having excellent antistatic properties, suitable for use in coating, printing, cast articles, and electronic parts.
2. Discussion of the Background
Ultraviolet-curable resins have been widely used for coating, printing, cast articles, electronic parts and the like, by employing the characteristic properties thereof such that the resin layer can be rapidly cured at normal temperatures by ultraviolet irradiation, in a high solid fractions or without solvents, as is described in "New Polymer Series", Shin Ko-bunshi Bunko, No. 21, Handbook to UV Curing Technology, Polymer Kanko-kai ed.
However, the cured layers derived from ordinary ultraviolet-curable resins have serious defects in that the specific surface resistance thereof is so high that static electricity is easily accumulated thereon. The accumulation of static electricity causes not only deposition of dust thereon to dirty the appearance of products but also damages on the products due to rubbing and abrasion. In order to overcome these defects, there has been proposed the use of a combination of ordinary ultraviolet-curable resins and ultraviolet-curable resins provided with antistatic properties (Japanese Patent Publication Nos. 14859/1974 and 22952/1974). Nevertheless, only the antistatic ultraviolet-curable resin present on the surface exhibits the antistatic effect, so that any antistatic agent present except for that on the surface layer may totally be useless, according to such a method. Accordingly, in order to achieve this objective, a large amount of an ultraviolet-curable resin having antistatic properties is required not only leading to an increase in production costs therefor but also as a result of the contamination by other components which are not necessarily required inside the curing resin layer, there has been the problem of some deterioration in the properties that have been sought in the ultraviolet-curable resins.
If attention is only focused on the problem of the antistatic effect being limited to the surface layer, an antistatic ultraviolet-curable resin may be applied on an ordinary ultraviolet-curable resin layer treated with ultraviolet curing, and then cured by ultraviolet irradiation again. However, the surface layer of the antistatic ultraviolet-cured resin according to the above method may be readily peeled off so that the antistatic effect may be exhibited only temporarily.